Mechanical seals, sometimes called end face shaft seals, are usually complex in design and call for precision or close tolerance fit between the various coacting parts. The seal assembly prevents flow of fluid from a high to a low pressure fluid contained on opposed sides of a bulkhead, as for example, the bulkhead of a pump housing which receives a rotating shaft therethrough. Mechanical seals must often work in regions of high temperatures and high pressure, and in some instances must be capable of operating in abrasive and corrosive fluids. For this reason, a continuous flush through the interior of the seal has sometimes been resorted to in order to prevent ingress of contaminant into the coacting seal parts. Others have placed seals in tandem so that a second seal is available for use after the first seal has failed, and still others have undergone great expense in filtering deleterious material from the fluid upstream of the pump, thereby reducing the probability of seal failure.
It would, therefore, be desirable to have made available an inexpensive end face shaft seal apparatus which operates with little or no drag, which is provided with means by which the interior of the seal is maintained free of abrasive material, which has a minimum of moving parts, and which can withstand a high temperature environment. Such a desirable seal is the subject of the present invention.